Multi-function machines have been recently developed. These machines commonly include the capability to print a digitally formatted document which is downloaded from a host computer. As is known in the art, the print function of the multi-function machine is realized by utilizing a laser and a polygon mirror to write information on a photoreceptor. The photoreceptor is subsequently placed in contact with a piece of paper which acquires the image written on the photoreceptor. Prior to this print function, a set-up time is required for rasterizing the document downloaded from the host computer. The machine is otherwise idle during this set-up time.
Prior art multi-function machines also commonly include the capability to digitally copy a document. As is known in the art, the digital copying aspect of these machines is realized through a Charge Coupled Device (CCD) which acquires a digital data representation of an image. The digital image data is then conveyed to the printer portion of the machine which yields a printed document. Typically, for large copying jobs, a set-up time is required as an automatic document feed moves documents into a proper position for scanning. The automatic document feed is a mechanical device which is relatively slow. As a result, the set-up time associated with the document feed reduces the efficiency of the multi-function machine.
Prior art multi-function machines may also include a capability to send and receive facsimile documents. A received facsimile document is usually printed in accordance with the printer aspect of the multi-function machine. A facsimile document to be sent is typically scanned and encoded by the CCD element of the multi-function machine.
Multi-function machines are commonly utilized by a number of users. For instance, a multi-function machine may be directly coupled to a number of computers or may be coupled to a local area network. The users of the computers may simultaneously initiate requests to print documents. At the same time, an individual may be standing at the machine and request that a copying job be performed. Moreover, an incoming facsimile job may simultaneously require the printer function of the machine.
Thus, it is readily obvious that contention problems may arise with a multi-function machine. A user of a multi-function machine naturally desires that progress be made on his or her job at all available times.